The chemical formula of (pastel) pyrope garnet as determined with the electron microprobe: (Mg 2.119  Fe 0.380  Mn 0.333 Ca 0.167) (Al 1.984 V 0.009 Cr 0.006) Si 3.000 

This is a typical formula. The exact analysis veried a small amount from point to point on the sample (in the 2d or 3d decimal place).  

This is a pyrope garnet. It has an almandine component (the Fe); it  has a spessartine component (the Mn); it has a grossular component (the Ca).

The color comes from the iron (Fe) which we know is mostly in the 2+ oxidation state. The vanadium and chromium are significant contributions to the color.

This garnet has about 13% almandine component.

Dr. George R. Rossman

Professor of Mineralogy
Division of Geological and Planetary Sciences
California Institute of Technology